The present invention relates to a special effect system for a television video signal, and particularly to a special effect system which produces special effects in which a video image is bent or turned, rolled up or made wavy with reference to a designated reference straight line.
In a special effect system for a television video signal, various special effects are generated by employing a digital video memory and producing a special write or read address therefor. To obtain such special address, a function generating circuit which comprises at least a multiplier, a divider, an adder and a subtractor is conventionally used, and thus the construction is extremely complicated. Particularly, in order to generate effects in which the video image is turned, rolled up or made wavy with reference to the designated reference straight line, it is necessary for a trigonometric function and a hyperbolic function to be generated. Conventionally, many multipliers, dividers, adders and subtracters are required for generating such functions. Further, for modifying the functions to be generated, the interconnections of these components must be changed, thus involving a disadvantageous complicated configuration.